Complications related to hydroxyapatite vertebral spacer in anterior cervical spine surgery.

STUDY DESIGN: This is a report of complications related to the hydroxyapatite vertebral spacer used for anterior cervical reconstructive surgery. Compression of the spinal cord by broken fragments of hydroxyapatite spacer as well as its surrounding radiolucent clear zone were observed in seven patients.

OBJECTIVES: To report complications related to the use of hydroxyapatite vertebral spacer for anterior cervical reconstructive surgery and to discuss how to prevent these complications.

SUMMARY OF BACKGROUND DATA: Despite previous articles reporting the clinical applications of hydroxyapatite vertebral spacer for the cervical spine, clinical reports regarding the long-term results of hydroxyapatite spacer for anterior cervical surgery and its complications have been limited.

METHODS: The authors reviewed patients who underwent anterior reconstructive surgery using the hydroxyapatite spacer at other hospitals and had postoperative complications related to hydroxyapatite spacer.

RESULTS: Seven patients previously treated by anterior cervical spine surgery using the hydroxyapatite vertebral spacer were referred to the authors because of unsatisfactory surgical outcomes. All the patients had a radiolucent clear zone around the spacer and experienced severe neck pain. Four had fracture of the hydroxyapatite spacer, and two had compression of the spinal cord by retropulsed fragments of broken hydroxyapatite spacers.

CONCLUSIONS: Although hydroxyapatite has been used in many medical fields because of its bioactive characteristics, its mechanical properties should be improved to lessen the risks of breakage and subsequent spinal cord compression. Gentle insertion maneuvers are also important to avoid the production of cracks inside the spacer.